The instant invention relates to electroplating, and more particularly to a novel electroplating solution recovery system wherein liquid is automatically transferred between rinse and plating tanks in order to achieve maximum electroplating solution recovery and effective pollution control and in order to maintain desired liquid levels in the electroplating and rinse tanks.
Electroplating processes are widely used in a variety of industries, including the jewelry industry, for providing protective and/or decorative platings on various types of articles. In this regard, in most small-scale electroplating operations, an article is plated by placing it in an electroplating tank containing an electroplating solution of a particular metal. The article is then electrically connected to one of two electrodes in the tank; and thereafter the electrodes are energized for a predetermined period of time to plate the article to a desired extent. After the article has been plated, it is disconnected from the respective electrode, removed from the tank and dipped in a first rinse tank (drag-out tank) to remove excess electroplating solution from the article. The article may then be rinsed in one or more additional rinse tanks, depending on the particular process.
During the course of an electroplating operation, portions of both the electroplating solution and the rinse solutions are lost from the various tanks through carry-over and evaporation as various articles are electroplated, and therefore both the electroplating solution and the rinse solutions must be frequently replenished. Heretofore, in most cases, these solutions have been replenished manually, although systems have been heretofore available wherein solutions have been automatically replenished through the use of level controls and pumps, etc. In most cases, the solution in an electroplating tank has been replenished with rinse solution from the first rinse tanks of the system, and the rinse solution in the first rinse tank has been replenished with rinse solution from the second rinse tank of the system, if there is one, or with water if there is only one rinse tank. In this manner, maximum recovery of the electroplating solution has been assured, although obviously frequent additions of chemicals to the plating tank have been required to maintain the necessary concentration therein.
The instant invention provides a novel electroplating solution system wherein liquid is automatically transferred as needed between various rinse tanks and between a first rinse tank and a plating tank to automatically replenish the solution levels in the various tanks while maintaining maximum plating solution recovery. Further, as a result of the high degree of effectiveness with which the system of the instant invention maximizes plating solution recovery, the amounts of pollutants or contaminants contained in waste water effluents from the system are effectively minimized. The electroplating solution system of the instant invention comprises an electroplating tank containing an electroplating solution, a first rinse tank containing a first rinse solution, and a first tubular interconnection which extends between the electroplating tank and the first rinse tank, so that one end of the first interconnection is disposed in the electroplating solution, and the other end thereof is disposed in the first rinse solution. In the preferred embodiment, the system further comprises a plurality of sequential rinse tanks containing sequential rinse solutions and a plurality of tubular interconnections which interconnect the various rinse tanks in series relation, the first rinse tank in the series, however, also being interconnected to the plating tank, as mentioned, and the last tank in the series being connected to a water supply for replenishing the solution level therein. Also, in the preferred embodiment, the system further comprises a check valve connected to the first tubular interconnection which permits the flow of liquid from the first rinse tank to the electroplating tank, but which prevents the flow of liquid from the electroplating tank to the first rinse tank. The electroplating tank and the rinse tanks are all disposed at approximately the same vertical heights, and all of the interconnections are maintained filled with the rinse solutions; and therefore, as the liquid level in the electroplating tank decreases, the first rinse solution is automatically transferred thereto from the first rinse tank through the first tubular interconnection by a siphoning process; and similarly, rinse solutions are transferred in series relation between the various other rinse tanks. The check valve prevents the flow of liquid from the electroplating tank into the first rinse tank, so that contamination of the first rinse solution is avoided. However, by using the first rinse solution from the first rinse tank to replenish the liquid in the electroplating tank, maximum recovery of the electroplating solution from the first rinse tank is assured, although obviously, the concentration of the chemicals in the electroplating solution must also be replenished from time to time as they are consumed in the electroplating process. Similarly, maximum recovery of plating solution from the additional rinse tanks is assured as solution is automatically transferred in series from tank to tank by siphoning. In any case, the instant invention provides an effective electroplating solution system wherein the level of the solution in an electroplating tank is continuously and automatically replenished. Further, when the electroplating solution system is embodied with a plurality of rinse tanks, the tanks are connected in sequence with interconnections extending therebetween so that the solutions in all of the tanks, with the exception of the last tank, are automatically replenished.
Accordingly, it is a primary object of the instant invention to provide an electroplating solution system wherein solution from a rinse tank is automatically added to an electroplating tank as required.
Another object of the instant invention is to provide an automatic electroplating solution system which does not require transfer pumps for transferring solutions to and from various tanks.
Another object of the instant invention is to provide an electroplating solution system wherein maximum recovery of the electroplating solution is assured.
An even further object of the instant invention is to provide an electroplating solution system wherein the chemical pollutants in water effluents from the system are minimized.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.